1. Field of the Invention
This invention relates to a light-emitting device including an organic compound material as a light emitting medium used for displaying images, a lighting, and the like.
2. Related Art
As a light-emitting device available in full color image display by arranging a plurality of light-emitting pixels in a matrix configuration (rows and columns), a light-emitting device available in full color display by combining electroluminescent (EL) elements, each of which emits light in different emission color (typically, red (R), green (G), and blue (B)) per pixel is well known. However, there has been a problem that emission lifetime varies by emission color. Further, there has been a problem that a precision technique for patterning is required.
As another method, a method of combining a blue light-emitting element and a color conversion layer can be nominated. There has been also a problem that high practical color conversion efficiency cannot be obtained according to this method. In addition, it has been problematic that a high efficiency blue light-emitting element has been required.
There is also a method that a white light-emitting element and a color filter are combined; however, there has been a problem that the usability of light emission is deteriorated, and so a high luminance white light-emitting element is required.